Developing apparatus, image forming apparatus, image forming system and image forming method

Abstract

A developer carrier has concave portions regularly arranged on the surface thereof and being rotatable with a developer thereon. A contact member is made of an elastic rubber material, is in contact with the surface of the developer carrier, and vibrates with the rotation of the developer carrier. A value obtained by dividing a movement speed of the surface at the time of rotation of the developer carrier by a pitch of the concave portions in a peripheral direction of the developer carrier is smaller than a peak vibrational frequency of the contact member when a loss tangent obtained by dividing a loss elastic modulus of the contact member by a storage elastic modulus is the greatest.

1. A developing apparatus comprising:
 a developer carrier having concave portions regularly arranged on the surface thereof and being rotatable with a developer thereon; and 
 a contact member being made of an elastic rubber material, being in contact with the surface of the developer carrier, and vibrating with the rotation of the developer carrier, 
 wherein the developing apparatus can be mounted on and demounted from an image forming apparatus body of an image forming apparatus; 
 wherein an operating temperature range is set in the image forming apparatus; and 
 wherein a value obtained by dividing a movement speed of the surface at the time of rotation of the developer carrier at a constant speed by a pitch of the concave portions in a peripheral direction of the developer carrier is smaller than a peak vibrational frequency of the contact member when a loss tangent obtained by dividing a loss elastic modulus of the contact member by a storage elastic modulus is the greatest at all temperatures in the operating temperature range. 
 
     
     
       2. The developing apparatus as set forth in  claim 1 , wherein the contact member is a layer thickness regulating member coming in contact with the surface to regulate the layer thickness of the developer held in the developer carrier. 
     
     
       3. The developing apparatus as set forth in  claim 1 ,
 wherein the contact member is in contact with the surface so that the longitudinal direction thereof is parallel to the axial direction of the developer carrier and an end in the width direction thereof faces the upstream in the rotation direction of the developer carrier; and 
 wherein a contact portion of the contact member, which is in contact with the surface is apart from the end in the width direction. 
 
     
     
       4. The developing apparatus as set forth in  claim 1 ,
 wherein the concave portions are two types of spiral grooves having different tilt angles about the peripheral direction, 
 wherein the two types of spiral grooves intersect each other to form a lattice shape, 
 wherein the developer carrier has square-like top faces surrounded with the two types of spiral grooves, and 
 wherein one of two diagonals of each square-like top face is parallel to the peripheral direction. 
 
     
     
       5. The developing apparatus as set forth in  claim 1 , wherein the contact member is made of thermoplastic elastomer. 
     
     
       6. The developing apparatus as set forth in  claim 1 , wherein the value obtained by dividing the movement speed of the surface at the time of rotation of the developer carrier by the pitch of the concave portions in the peripheral direction of the developer carrier is smaller than the peak vibrational frequency of the contact member when the loss tangent is the greatest and is smaller than a second peak vibrational frequency at which the loss tangent is a half of the greatest value. 
     
     
       7. An image forming apparatus comprising:
 an image carrier holding a latent image; and 
 a developing apparatus developing the latent image held by the image carrier with a developer, 
 wherein the developing apparatus includes:
 a developer carrier having concave portions regularly arranged on the surface thereof and being rotatable with the developer thereon; and 
 a contact member being made of an elastic rubber material, being in contact with the surface of the developer carrier, and vibrating with the rotation of the developer carrier; 
 
 wherein an operating temperature range is set in the image forming apparatus; and 
 wherein a value obtained by dividing a movement speed of the surface at the time of rotation of the developer carrier at a constant speed by a pitch of the concave portions in a peripheral direction of the developer carrier is smaller than a peak vibrational frequency of the contact member when a loss tangent obtained by dividing a loss elastic modulus of the contact member by a storage elastic modulus is the greatest at all temperatures in the operating temperature range. 
 
     
     
       8. An image forming system comprising:
 a computer; and 
 an image forming apparatus connectable to the computer, wherein the image forming apparatus includes:
 an image carrier holding a latent image; and 
 a developing apparatus developing the latent image held by the image carrier with a developer; 
 
 wherein the developing apparatus includes:
 a developer carrier having concave portions regularly arranged on the surface thereof and being rotatable with the developer thereon; and 
 a contact member being made of an elastic rubber material, being in contact with the surface of the developer carrier, and vibrating with the rotation of the developer carrier; 
 
 wherein an operating temperature range is set in the image forming apparatus; and 
 wherein a value obtained by dividing a movement speed of the surface at the time of rotation of the developer carrier at a constant speed by a pitch of the concave portions in a peripheral direction of the developer carrier is smaller than a peak vibrational frequency of the contact member when a loss tangent obtained by dividing a loss elastic modulus of the contact member by a storage elastic modulus is the greatest at all temperatures in the operating temperature range. 
 
     
     
       9. A developing apparatus comprising:
 a developer carrier having concave portions regularly arranged on the surface thereof and being rotatable with a developer thereon; and 
 a contact member being made of an elastic rubber material, being in contact with the surface of the developer carrier, and vibrating with the rotation of the developer carrier, 
 wherein the developing apparatus can be mounted on and demounted from an image forming apparatus body of an image forming apparatus; 
 wherein an operating temperature range is set in the image forming apparatus; and 
 wherein a value obtained by dividing a movement speed of the surface at the time of rotation of the developer carrier at a constant speed by a pitch of the concave portions in a peripheral direction of the developer carrier has the same magnitude of a vibrational frequency at which the storage elastic modulus is smaller than the loss elastic modulus among vibrational frequencies smaller than a peak vibrational frequency of the contact member when a loss tangent obtained by dividing a loss elastic modulus of the contact member by a storage elastic modulus is the greatest at all temperatures in the operating temperature range. 
 
     
     
       10. The developing apparatus as set forth in  claim 9 , wherein the contact member is a layer thickness regulating member coming in contact with the surface to regulate the layer thickness of the developer held in the developer carrier. 
     
     
       11. The developing apparatus as set forth in  claim 9 , wherein the concave portions are two types of spiral grooves having different tilt angles about the peripheral direction,
 wherein the two types of spiral grooves intersect each other to form a lattice shape; 
 wherein the developer carrier has square-like top faces surrounded with the two types of spiral grooves; and 
 wherein one of two diagonals of each square-like top face is parallel to the peripheral direction. 
 
     
     
       12. An image forming apparatus comprising:
 an image carrier holding a latent image; and 
 a developing apparatus developing the latent image held by the image carrier with a developer, 
 wherein the developing apparatus includes:
 a developer carrier having concave portions regularly arranged on the surface thereof and being rotatable with a developer thereon; and 
 a contact member being made of an elastic rubber material, being in contact with the surface of the developer carrier, and vibrating with the rotation of the developer carrier; 
 
 wherein an operating temperature range is set in the image forming apparatus; and 
 wherein a value obtained by dividing a movement speed of the surface at the time of rotation of the developer carrier at a constant speed by a pitch of the concave portions in a peripheral direction of the developer carrier has the same magnitude of a vibrational frequency at which the storage elastic modulus is smaller than the loss elastic modulus among vibrational frequencies smaller than a peak vibrational frequency of the contact member when a loss tangent obtained by dividing a loss elastic modulus of the contact member by a storage elastic modulus is the greatest at all temperatures in the operating temperature range. 
 
     
     
       13. An image forming system comprising:
 a computer; and 
 an image forming apparatus connectable to the computer, 
 wherein the image forming apparatus includes:
 an image carrier holding a latent image; and 
 a developing apparatus developing the latent image held by the image carrier with a developer; 
 
 wherein the developing apparatus includes:
 a developer carrier having concave portions regularly arranged on the surface thereof and being rotatable with a developer thereon; and 
 a contact member being made of an elastic rubber material, being in contact with the surface of the developer carrier, and vibrating with the rotation of the developer carrier; 
 
 wherein an operating temperature range is set in the image forming apparatus; and 
 wherein a value obtained by dividing a movement speed of the surface at the time of rotation of the developer carrier at a constant speed by a pitch of the concave portions in a peripheral direction of the developer carrier has the same magnitude of a vibrational frequency at which the storage elastic modulus is smaller than the loss elastic modulus among vibrational frequencies smaller than a peak vibrational frequency of the contact member when a loss tangent obtained by dividing a loss elastic modulus of the contact member by a storage elastic modulus is the greatest at all temperatures in the operating temperature range. 
 
     
     
       14. A developing apparatus comprising:
 a developer carrier having concave portions regularly arranged on the surface thereof and being rotatable with a developer thereon; and 
 a contact member being made of an elastic rubber material, being in contact with the surface of the developer carrier, and vibrating with the rotation of the developer carrier, 
 wherein the developing apparatus can be mounted on and demounted from an image forming apparatus body of an image forming apparatus; 
 wherein an operating temperature range is set in the image forming apparatus; and 
 wherein a value obtained by dividing a movement speed of the surface at the time of rotation of the developer carrier at a constant speed by a pitch of the concave portions in a peripheral direction of the developer carrier has the same magnitude of a vibrational frequency at which the loss elastic modulus is smaller than the storage elastic modulus among vibrational frequencies smaller than a peak vibrational frequency of the contact member when a loss tangent obtained by dividing a loss elastic modulus of the contact member by a storage elastic modulus is the greatest at all temperatures in the operating temperature range. 
 
     
     
       15. The developing apparatus as set forth in  claim 14 , wherein the contact member is a layer thickness regulating member coming in contact with the surface to regulate the layer thickness of the developer held in the developer carrier. 
     
     
       16. The developing apparatus as set forth in  claim 15 , wherein the layer thickness regulating member is in contact with the surface so that the longitudinal direction thereof is parallel to the axial direction of the developer carrier and an end in the width direction faces the upstream in the rotation direction of the developer carrier, and
 wherein a contact portion of the layer thickness regulating member is apart from the end in the width direction. 
 
     
     
       17. The developing apparatus as set forth in  claim 14 ,
 wherein the concave portions are two types of spiral grooves having different tilt angles about the peripheral direction; 
 wherein the two types of spiral grooves intersect each other to form a lattice shape; 
 wherein the developer carrier has square-like top faces surrounded with the two types of spiral grooves; and 
 wherein one of two diagonals of each square-like top face is parallel to the peripheral direction. 
 
     
     
       18. An image forming apparatus comprising:
 an image carrier holding a latent image; and 
 a developing apparatus developing the latent image held by the image carrier with a developer; 
 wherein the developing apparatus includes: 
 a developer carrier having concave portions regularly arranged on the surface thereof and being rotatable with a developer thereon; and 
 a contact member being made of an elastic rubber material, being in contact with the surface of the developer carrier, and vibrating with the rotation of the developer carrier; 
 wherein an operating temperature range is set in the image forming apparatus; and 
 wherein a value obtained by dividing a movement speed of the surface at the time of rotation of the developer carrier at a constant speed by a pitch of the concave portions in a peripheral direction of the developer carrier has the same magnitude of a vibrational frequency at which the loss elastic modulus is smaller than the storage elastic modulus among vibrational frequencies smaller than a peak vibrational frequency of the contact member when a loss tangent obtained by dividing a loss elastic modulus of the contact member by a storage elastic modulus is the greatest at all temperatures in the operating temperature range. 
 
     
     
       19. An image forming system comprising:
 a computer; and 
 an image forming apparatus connectable to the computer, 
 wherein the image forming apparatus includes:
 an image carrier holding a latent image; and 
 a developing apparatus developing the latent image held by the image earner with a developer; 
 
 wherein the developing apparatus includes:
 a developer carrier having concave portions regularly arranged on the surface thereof and being rotatable with a developer thereon; and 
 a contact member being made of an elastic rubber material, being is contact with the surface of the developer carrier, and vibrating with the rotation of the developer carrier; and 
 
 wherein an operating temperature range is set in the image forming apparatus; and 
 wherein a value obtained by dividing a movement speed of the surface at the time of rotation of the developer carrier at a constant speed by a pitch of the concave portions in a peripheral direction of the developer carrier has the same magnitude of a vibrational frequency at which the loss elastic modulus is smaller than the storage elastic modulus among vibrational frequencies smaller than a peak vibrational frequency of the contact member when a loss tangent obtained by dividing a loss elastic modulus of the contact member by a storage elastic modulus is the greatest at all temperatures in the operating temperature range. 
 
     
     
       20. An image forming apparatus in which an operating temperature range is set, comprising:
 an image carrier holding a latent image; 
 a developer carrier having concave portions regularly arranged on a surface thereof, being rotatable with a developer held thereon, and developing the latent image with the developer held thereon; 
 a contact member made of an elastic rubber material being in contact with the surface of the developer carrier and vibrating with the rotation of the developer carrier; and 
 a controller starting the rotation of the developer carrier, then raising a rotation speed of the developer carrier to a first rotation speed at which a movement speed of the surface at the time of rotation of the developer carrier is greater than a product of a pitch of the concave portions in a peripheral direction of the developer carrier and a peak vibrational frequency of the contact member when a loss tangent obtained by dividing a loss elastic modulus of the contact member by a storage elastic modulus is the greatest at all temperatures in the operating temperature range, lowering the rotation speed of the developer carrier to a second rotation speed at which the movement speed is smaller than the product after the rotation speed of the developer carrier becomes the first rotation speed, and allowing the developer carrier rotating at the second rotation speed to develop the latent image. 
 
     
     
       21. The image forming apparatus as set forth in  claim 20 , further comprising a developing bias application section applying a developing bias for developing the latent image to the developer carrier,
 wherein the controller lowers the rotation speed of the developer carrier from the first rotation speed to the second rotation speed via a third rotation speed at which the movement speed is equal to the product after the rotation speed of the developer carrier becomes the first rotation speed and starts the application of the developing bias from the developing bias application section after the rotation speed of the developer carrier becomes the third rotation speed. 
 
     
     
       22. The image forming apparatus as set forth in  claim 21 , wherein the controller starts the application of the developing bias from the developing bias application section after a time point in a time period, when a portion, on the surface of the developer carrier, in contact with the contact member when the rotation speed of the developer carrier becomes the third rotation speed moves to a position opposed to the image carrier with an additional rotation of the developer carrier, after the rotation speed of the developer carrier becomes the third rotation speed. 
     
     
       23. An image forming apparatus in which an operating temperature range is set, comprising:
 an image carrier holding a latent image; 
 a developer carrier having concave portions regularly arranged on a surface thereof, being rotatable with a developer held thereon, and developing the latent image with the developer held thereon; 
 a contact member made of an elastic rubber material being in contact with the surface of the developer carrier and vibrating with the rotation of the developer carrier; and 
 a controller allowing the developer carrier which rotates at a fifth rotation speed at which a movement speed of the surface at the time of rotation of the developer carrier is smaller than a product of a pitch of the concave portions in a peripheral direction of the developer carrier and a peak vibrational frequency of the contact member when a loss tangent obtained by dividing a loss elastic modulus of the contact member by a storage elastic modulus is the greatest at all temperatures in the operating temperature range, to develop the latent image, raising the rotation speed of the developer carrier to a fourth rotation speed at which the movement speed is greater than the product after the developing of the latent image is ended, and stopping the rotation of the developer carrier after the rotation speed of the developer carrier becomes the fourth rotation speed. 
 
     
     
       24. The image forming apparatus as set forth in  claim 23 , further comprising a developing bias application section applying a developing bias for developing the latent image to the developer carrier,
 wherein the controller raises the rotation speed of the developer carrier from the fifth rotation speed to the fourth rotation speed via a third rotation speed at which the movement speed is equal to the product after ending the developing of the latent image, and stops the application of the developing bias from the developing bias application section before a time point in a time period, when a portion, on the surface of the developer carrier, in contact with the contact member when the rotation speed of the developer carrier becomes the third rotation speed moves to a position opposed to the image carrier with an additional rotation of the developer carrier, after the rotation speed of the developer carrier becomes the third rotation speed. 
 
     
     
       25. The image forming apparatus as set forth in  claim 24 , wherein the controller stops the application of the developing bias from the developing bias application section before the rotation speed of the developer carrier becomes the third rotation speed. 
     
     
       26. The image forming apparatus as set forth in  claim 23 , further comprising a rake-out member coming in contact with the surface of the developer carrier to rake out the developer from the developer carrier,
 wherein the controller stops the rotation after a time point in a time period, when a portion, on the surface of the developer carrier, in contact with the contact member when the rotation speed of the developer carrier becomes the third rotation speed moves to a position opposed to the image carrier with an additional rotation of the developer carrier, after the rotation speed of the developer carrier becomes the third rotation speed, at the time of stopping the rotation of the developer carrier after the rotation speed of the developer carrier becomes the fourth rotation speed. 
 
     
     
       27. An image forming system comprising:
 a computer; and 
 an image forming apparatus being connectable to the computer, 
 wherein an operating temperature range is set in the image forming apparatus; 
 wherein the image forming apparatus includes: 
 an image carrier holding a latent image; 
 a developer carrier having concave portions regularly arranged on a surface thereof, being rotatable with a developer held thereon, and developing the latent image with the developer held thereon; 
 a contact member made of an elastic rubber material being in contact with the surface of the developer carrier and vibrating with the rotation of the developer carrier; and 
 a controller starting the rotation of the developer carrier, then raising a rotation speed of the developer carrier to a first rotation speed at which a movement speed of the surface at the time of rotation of the developer carrier is greater than a product of a pitch of the concave portions in a peripheral direction of the developer carrier and a peak vibrational frequency of the contact member when a loss tangent obtained by dividing a loss elastic modulus of the contact member by a storage elastic modulus is the greatest at all temperatures in the operating temperature range, lowering the rotation speed of the developer carrier to a second rotation speed at which the movement speed is smaller than the product after the rotation speed of the developer carrier becomes the first rotation speed, and allowing the developer carrier rotating at the second rotation speed to develop the latent image. 
 
     
     
       28. An image forming system comprising:
 a computer; and 
 an image forming apparatus being connectable to the computer, 
 wherein an operating temperature range is set in the image forming apparatus; 
 wherein the image forming apparatus includes:
 an image carrier holding a latent image; 
 a developer carrier having concave portions regularly arranged on a surface thereof, being rotatable with a developer held thereon, and developing the latent image with the developer held thereon; 
 
 a contact member made of an elastic rubber material being in contact with the surface of the developer carrier and vibrating with the rotation of the developer carrier; and 
 a controller allowing the developer carrier which rotates at a fifth rotation speed at which a movement speed of the surface at the time of rotation of the developer carrier is smaller than a product of a pitch of the concave portions in a peripheral direction of the developer carrier and a peak vibrational frequency of the contact member when a loss tangent obtained by dividing a loss elastic modulus of the contact member by a storage elastic modulus is the greatest at all temperatures in the operating temperature range, to develop the latent image, raising the rotation speed of the developer carrier to a fourth rotation speed at which the movement speed is greater than the product after the developing of the latent image is ended, and stopping the rotation of the developer carrier after the rotation speed of the developer carrier becomes the fourth rotation speed. 
 
     
     
       29. An image forming method in an image forming apparatus, comprising:
 a step of raising a rotation speed of a developer carrier to a first rotation speed at which a movement speed of a surface of the developer carrier at the time of rotation of the developer carrier is greater than a product of a pitch of concave portions in a peripheral direction of the developer carrier and a peak vibrational frequency of a contact member when a loss tangent obtained by dividing a loss elastic modulus of the contact member by a storage elastic modulus thereof is the greatest at all temperatures in an operating temperature range of the image forming apparatus after starting the rotation of the developer carrier, the developer carrier having the concave portions regularly arranged on the surface, being rotatable with a developer held thereon, and developing the latent image with the developer held thereon, the contact member being made of an elastic rubber material being in contact with the surface of the developer carrier and vibrating with the rotation of the developer carrier; 
 a step of lowering the rotation speed of the developer carrier to a second rotation speed at which the movement speed is smaller than the product after the rotation speed of the developer carrier becomes the first rotation speed; and 
 a step of allowing the developer carrier rotating at the second rotation speed to develop the latent image. 
 
     
     
       30. An image forming method in an image forming apparatus, comprising:
 a step of allowing a developer carrier to develop a latent image, the developer carrier rotating at a fifth rotation speed at which a movement speed of a surface of the developer carrier at the time of rotation of the developer carrier is smaller than a product of a pitch of concave portions in a peripheral direction of the developer carrier and a peak vibrational frequency of a contact member when a loss tangent obtained by dividing a loss elastic modulus of the contact member by a storage elastic modulus thereof is the greatest at all temperatures in an operating temperature range of the image forming apparatus, the developer carrier having the concave portions regularly arranged on the surface, being rotatable with a developer held thereon, and developing the latent image with the developer held thereon, the contact member being made of an elastic rubber material being in contact with the surface of the developer carrier and vibrating with the rotation of the developer carrier; 
 a step of raising the rotation speed of the developer carrier to a fourth rotation speed at which the movement speed is greater than the product after the rotation speed of the developer carrier becomes the first rotation speed after ending the developing of the latent image; and 
 a step of stopping the rotation of the developer carrier after the rotation speed of the developer carrier becomes the fourth rotation speed.